Crushing chamber for a centrifugal impact rock crushing machine

ABSTRACT

A CRUSHING CHAMBER FOR A CENTRIFUGAL IMPACT ROCK CRUSHING MACHINE IS DESCRIBED, HAVING A ROTATABLE TURNTABLE FOR ACCELERATING THE ROCK TO HIGH VELOCITIES AND THEN DISCHARGING THE ROCK AGAINST INDEPENDENT WEAR RESISTANT IMPACT BLOCKS CIRCUMSCRIBING THE TURNTABLE.

Sept. 20, 1911 D. R. WARREN 3,60 ,1

CRUSHING CHAMBER FOR CENTRIFUGAL IMPACT ROCK G RUSH MACHINE Filed Feb. 27, 1969 Y 3 Sheets-Sheet 1 NVENTOR. oun/d R. WARREN A 1 BY 601m p 20, 1971 D. R. WARREN 3,606,182

CRUSHING CHAMBER FOR A CENTRIFUGAL IMPACT ROCK CRUSHING MACHINE Filed Feb. 27, 1969 3 Sheets-Sheet 2 INVENTOR.

Id R. WARREN BY mm, M.9M

Sept. 20, 1971 o. R. WARREN CRUSHING CHAMBER FOR A CENTRIFUGAL IMPACT ROCK CRUSHING MACHINE 5 Sheets-Sheet :3

Filed Feb. 27, 1969 INVENTOR.

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United States Patent 3,606,182 CRUSI-IING CHAMBER FOR A CENTRIFUGAL IMPACT ROCK CRUSHING MACHINE Donald R. Warren, Spokane, Wash., assignor to Cimco, Inc., Spokane, Wash. Filed Feb. 27, 1969, Ser. No. 803,001 Int. Cl. B02c 13/18, 13/28, 19/00 U.S. Cl. 241275 7 Claims ABSTRACT OF THE DISCLOSURE A crushing chamber for a centrifugal impact rock crushing machine is described, having a rotatable turntable for accelerating the rock to high velocities and then discharging the rock against independent Wear resistant impact blocks circumscribing the turntable.

BACKGROUND OF THE INVENTION This invention relates to centrifugal impact rock crushing machines and more particularly to the crushing chambers therein.

For many years, the roll-type rock crushing machines have dominated the rock crushing industry even though centrifugal rock crushing machines had certain advantages in producing rock aggregate more similar to the crystalline structure of the rock.

In a roll-type rock crushing machine, the rock is fed between counter-rotating rolls which crush the rock therebetween. In such machines, squeezing forces are applied to the rock to farcture the rock into many pieces. Many of the pieces are sliver-like in shape and are undesirable from the standpoint of uniformity of size and quality.

In a centrifugal impact type rock crushing machine the rock is fed centrally onto a turntable that is rotated at a high r.p.m. to accelerate the rock outwardly to a high velocity and against wear resistant anvil members to bring the rock to a sudden stop to cause the deceleration forces to break the rock along the crystalline planes of that rock.

The principal disadvantage of the centrifugal impact rock crushing machine has been the excessive wear of the parts of the crushing chamber in a short period of time. Frequently the wear becomes so severe that most of the crushing chamber has to be replaced. It has been difficult to develop an impact rock crushing machine that may be maintained in operation for any substantial length of time. There have been many attempts, some of them commercially, however, their performance has been less than desired or anticipated.

One of the principal objects of this invention is to provide a centrifugal impact rock crushing machine having a greatly improved performance capability.

An additional object is to greatly increase the operational life of the machine and substantially increase the interval between maintenance and replacement.

A further object of this invention is to provide a rock crushing chamber having wear components of longer life.

An additional object of this invention is to provide a crushing chamber with a new and unobvious mounting for impeller shoes to prevent the movement of the impeller shoes during operation and to enable the impeller shoes to be easily and quickly removed when they be come worn.

A still further object of this invention is to provide wear plates of a certain shape and configuration to prevent the wear of the turntable and the lid of the chamber.

These and other objects of this invention will become apparent upon the reading of the following detailed description of a preferred embodiment.

3,606,182 Patented Sept. 20, 1971 ice A preferred embodiment of this invention is illustrated in the accompanying drawings, in which:

FIG. 1 is a fragmentary exploded perspective view of a crushing chamber for a centrifugal rock crushing machine illustrating the many parts of the chamber including the lid, wear plates for the lid, a turntable, wear plates for the turntable, impeller brackets, impeller shoes, impact blocks and mounting brackets for the impact blocks;

FIG. 2 is a perspective assembled view of the rock crushing chamber with the lid tilted upward to expose wear plates mounted to the under side of the lid;

FIG. 3 is a plan view of the crushing chamber with the lid removed to emphasize the location and spacing of the many parts of the crushing chamber;

FIG. 4 is a fragmentary plan view of a section of the turntable showing an impeller shoe being mounted to an impeller bracket;

FIG. 5 is a fragmentary cross sectional view taken along line 55 in FIG. 3 showing the face of the impeller shoe;

FIG. 6 is a fragmentary plan view showing the angle relationship of the impeller shoes and impact blocks;

FIG. 7 is a fragmentary cross sectional view taken along line 77 in FIG. 1 with the lid wear plates bolted to the lid and the lid clamped to the tank of the rock crushing chamber.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT A centrifugal impact rock crushing machine 10 is illustrated in FIGS. 1 and 2 having a cylindrical tank 11 with a crushing chamber 12 therein for receiving rock and crushing the rock into smaller pieces. The crushing chamber is closed by a lid 13.

One of the principal parts of the crushing chamber 12 is a turntable 14 that is mounted on a pedestal 15 (FIG. 1). The turntable 14 is connected to the upper end of a vertical drive shaft 16 that rotates the turntable at a high r.p.m. about a vertical axis Y to accelerate the rock aggregate to a high velocity. For best results the turntable should be rotated between 1500 and 2100 r.p.m. The pedestal 15 is mounted on a cross support 17 that extends between opposite sides of the cylindrical tank 11. As shown in FIG. 2 a motor 18 is mounted outside the cylindrical tank with a conventional drive train (not shown) extending through the cross support 17 to the lower end of the drive shaft 16.

A conveyor 20 is mounted beneath the cylindrical tank to receive the crushed rock as it descends from the crushing chamber to carry the crushed rock from the crushing machine.

The turntable 14 is circular in shape and has a Wear resistant center cone 22 with an apex at the center of the turntable. A plurality of impeller brackets 23 are evenly spaced about the turntable in a generally radial orientation to support wear resistant impeller shoes 24 thereon. The impeller shoes 24 receive the rocks as the turntable is rotated and guide the rocks outwardly, discharging the rocks in a narrow spray band at high velocities beyond the periphery of the turntable.

Each impeller bracket 23 has an elongated body 26 (FIG. 4) that is mounted in a radial orientation on the turntable. A brace 27 is aflixed to the back of the elongated body and is rigidly affixed to the upper surface of the turntable 14. The elongated body 26 has an outer end 28 that extends outwardly beyond the periphery of the turntable and is secured to the turntable. The elongated body 26 has a horizontal aperture 29 formed therethrough in a generally transverse orientation. A side shoulder 30 is formed on the side of the body 26.

Each impeller shoe 14 has an elongated body with an impeller face 32 (FIG. that is substantially U-shaped with an upper side lip 33 and a lower side lip 34 for restricting and guiding the flow of the rock to a narrow spray band to control the trajectory of the rock as the rock is accelerated.

Each impeller shoe 14 is angularly positioned on the turntable with the outer end forward of the inner end in the direction of rotation of the turntable defining a positive angle a between the impeller face 32 and a radial line R that extends from the vertical axis Y intersecting the end of the impeller shoe as shown in FIG. 6. It has been found that greatly improved performance is obtained when angle a is between 5 and 15.

A back shoulder 35 (FIG. 4) is formed on the im-' peller body for engaging the side shoulder 30 of the impeller bracket to prevent the radial movement of the impeller shoe as the turntable is rotated. A shaft or stud 36 (FIG. 4) is formed on the back of the impeller shoe that extends through the aperture 29 of the impeller bracket to secure the impeller shoe to the impeller bracket.

A pin aperture 37 (FIG. 4) is formed radially through the shaft 36 in a direction that is downward and outward in relation to the turntable. A pin means 38, such as a cotter pin, extends into the pin aperture 38 to hold the impeller shoe to the impeller bracket. The direction of the pin aperture 37 is such that the pin 38 does not need to be secured in the aperture 37 because the centrifugal force acting on the pin 38 when the turntable is rotating, maintains the pin in the aperture 37, but permits the pin to be easily and rapidly removed from the pin aperture 37 when the turntable is not rotating to provide rapid and convenient replacement of the impeller shoes after they become worn.

A first set of wear plates 40 are replaceably mounted on the upper surface of the turntable 14 to protect and prevent wear of the turntable. Each of the wear plates 40 is pie-shaped with a fiat pie-shaped section 41 and a downwardly extending skirt 42 that protects the edge and periphery of the turntable 14. The arced edge of each of the wear plates 40 curves radially outward opposite to the direction in which the turntable is rotating to discharge the accelerating rock beyond the periphery of the turntable. To be more specific the radial distance of the wear plate at point 44 is less than the radial distance of the wear plate at point 45 to form an outwardly extending edge are.

A circular impact ring 47 is mounted to the inside of the cylindrical tank 11 surrounding the turntable 14. The impact ring is supported by braces 48 that are welded or otherwise secured to the cylindrical tank 11. A plurality of evenly spaced L-shaped horizontal brackets 50 are secured to the inside of the ring for supporting a plurality of corresponding impact or crushing blocks 53 facing the direction of rotation of the turntable for receiving and abruptly stopping the outward movement of the rocks to cause the rocks to disintegrate from the deceleration forces exerted on the rock. Each of the L-shaped brackets 50 have a leg 51 and a leg 52. The leg 52 has a rectangular slot 59 formed therein extending from the upper surface of the leg downwardly.

Each block 53 is mounted on the brackets 50 so that a portion of the impact face is perpendicular to the trajectories of the rocks as the rocks are discharged from the turntable 14. To accomplish this each block is mounted on the bracket to set the face at a prescribed angle b, which is the angle between the face and a radial line R when the line R intersects the block at the closest point to the turntable. It has been found that when the angle b is between 117 and 127 high performance is achieved.

Each of the impact blocks has a square stud 54 extending from the back thereof that fits within a corresponding rectangular slot 59 to enable the impact blocks to be readily removed from the rectangular slot 59 and vertically rotated in a multiple of 90 degrees, and then reposigioned in the slot to greatly increase the life of the blocks An enlarged head 55 (FIG. 6) is mounted on the end of the stud 54 to prevent the block from falling from the bracket.

The lid 13 has a central inlet 57 formed therethrough for feeding the rock into the crushing chamber and onto the central cone 22 of the turntable.

A second set of wear plates 58 is mounted on the underside of the lid 13 to prevent the wear of the lid 13 during the operation of the rock crushing machine. The Wear plates 58 are divided into an inner ring 61} and an outer ring 61. The inner ring of wear plates are bolted to the lid surrounding the inlet 57 by bolts 62 (FIG. 10). The wear plates of the inner ring have embossed annular ring sections 63 circumscribing countersunk bolt holes to prevent the wearing of the heads of the bolts. The outer ring 61 of the wear plates are also bolted to the lid by countersunk bolts 65. Embossed annular ring sections 66 are formed about the bolt holes to prevent the wear of the heads of the bolts.

An important feature of the wear plates of the outer ring is that the wear plates have skirts 67 that extend downwardly for protecting the interior of the cylindrical tank near its upper end. The skirt 67 blends into the major portion of the wear plate by a substantial radius of curvature 68 to reduce the Wear effect at the corner of the crushing chamber.

As shown in FIGS. 1, 2 and 7, clamp means 70 releasably interconnect the lid to the cylindrical tank. The lid 13 may be easily removed to provide maintenance and replacement access to the crushing chamber.

The impeller shoes 24, the Wear plates 40, the impact blocks 53 and the wear plates 40 and 58 are made of fine grained alloys that are highly wear resistant to the abrasive action of the rocks.

The precise angular and space relationship between the crushing chamber elements may be varied somewhat depending upon the size and amount of the aggregate being crushed and the size of the desired end product. For crushing aggregate of a size 1% inches or less, the following relationships and component sizes were found to produce far better results than achieved by other commercially available machines:

The following are the test results utilizing a machine embodying this invention:

Aggregate infeed. Out product, percent percent Screen size passing passing ,Frequently in the cement industry the crushed rock must be able to pass through a #4 screen to be considered usable. It is often referred to as pay material. It has been found that by utilizing an impact crushing machine embodying this invention, approximately 33 tons per hour of pay material can be produced from to A" rock.

What is claimed as the invention is:

1. In a centrifugal rock crushing machine having an impeller assembly rotating about a vertical axis for centrally receiving rock and throwing the rock outward against a plurality of evenly spaced anvil surfaces circumscribing the impeller assembly, said impeller assembly having a radially extending shoe with a wear resistant surface for engaging the rock and directing the rock outward, said shoe being angularly positioned with the outer end thereof forward of the inner end in the direction of rotation and at an angle of 5 to 15 between the wear resistant surface and a radial line from said axis through the outer end of the shoe, and each of said anvil surfaces facing the direction of rotation at an angle of 117 to 127 with respect to a radial line from said axis through the closest point of the anvil surface to the was 2. In an impact rock crushing machine as defined in claim 1, in which the impeller assembly is rotated at a speed of 1500 to 2100 rpm. and the distance from said axis to the outer end of the impeller shoe is from 13 to 16 inches.

3. In an impact rock crushing machine as defined in claim 1 for crushing aggregate having a size of 1% inches or less and in which the radial distance from the impeller assembly to the closest point on the anvil surface is approximately 2% inches.

4. In an impact rock crushing machine as defined in claim 1 in which the angle between said radial line and the shoe surface is 8 to 11 and the angle between the radial line and the impact surface is 120 to 123.

5. In an impact rock crushing machine having a crushing chamber enclosed by a lid with:

(a) a turntable positioned centrally in the chamber for rotation about a vertical axis;

(b) drive means for rotating the turntable at a speed between 1500 and 2100 rpm;

(0) impeller brackets mounted on the turntable;

(d) radial impeller shoes mounted to the impeller brackets to receive the rock and discharge the rock from the turntable at high velocities, each of said shoes being angularly positioned with the outer end thereof forward of the inner end in the direction of 6 rotation and at an angle of 5 to 15 between the shoe and a radial line from the vertical axis through the outer end of the shoe;

(e) impact surfaces surrounding the turntable facing the direction of rotation at an angle of 117 to 127 with respect to a radial line from the vertical axis through the closest point of the impact surface to receive the rocks and cause the rocks to break into smaller pieces.

6. In the impact rock crushing machine as defined in claim 5 wherein the crushing chamber includes a first set of wear plates mounted on the turntable between the impeller brackets to prevent wear of the turntable in which each wear plate has an outer edge that extends radially outward of the periphery of the turntable in an increasing radius opposite the direction of rotation to discharge the rock beyond the periphery of the turntable.

7. In a centrifugal rock crushing machine as defined in claim 5 wherein each of the impeller shoes has a shaft that extends outward therefrom and through an aperture formed in a corresponding impeller bracket and wherein the shaft is held in such aperture by a pin means that extends radially through the end of said shaft in a direction which maintains the pin means in the end of the shaft as the turntable rotates but which enables the pin to be slidably removed from the end of the shaft when the turntable is stopped to readily remove the impeller shoe from the impeller bracket.

References Cited UNITED STATES PATENTS 3,000,579 9/1961 Bridgewater 24l275 3,088,685 5/1963 Bridgewater 241-275X 3,148,840 9/ 1964 Behnke 24l275 3,258,211 6/1966 Behnke 241275 3,474,974 10/ 1969 Wood 24l--275 FOREIGN PATENTS 240,323 8/1962 Australia 24 1-275 DONALD G. KELLY, Primary Examiner 

